You can report a serious online problem to the Police here.
Childline
If you are not feeling happy or something has upset you, you can talk to Childline. Childline is free to contact on 0800 1111 or online here. Childline counsellors are there to take calls 24 hours a day, 7 days a week from children and young people under 19.
Report Remove
Report Remove is here to help young people under 18 in the UK to confidentially report sexual images and videos of themselves and remove them from the internet.